I applied a BSE on my girlfriends jet black and it looks good. It was the first skin I had applied in like 6 years so it took forever and I'm certain I could do a better job if I did it again.
Then I applied a Slickwraps Naked on my jet black 7 plus and the corner flaps overlapped the top and bottom folded part and if I forced it to not over lap then it creased. I tried heating the corners over an over but couldn't get a good fit. I tore that wrap off and tried the second wrap in the pack and the corner pieces were still too long. I took out some very sharp scissors and cut the absolutely tiniest piece off and that solved the over lap problem. However, either from the cut or possibly just the fit, the seam of the corners are still visible to me. I'm not sure that I'm annoyed enough to try again but if the corners start to peel up at all then I will. If I hand my phone to someone to look at they don't notice a skin at all unless I say look at the corners. Besides the corners, I like the cutouts and precision of the Slickwraps over the BSE.
That's been my experience thus far. Not a single micro scratch or anything on the phone but I only wipe it with the micro fiber cloth from my sunglasses before putting on the new skin and have not used it without a skin. The skin does a great job of not showing finger prints and smudges compared to the natural jet black finish.